Loxoprofen has an excellent medicinal effect as a non-steroidal anti-inflammatory analgesic agent derived from phenylpropionic acid and has been widely used as an oral medicine. Some external preparations contain loxoprofen are also proposed. For example, Patent Document 1 discloses a patch comprising loxoprofen and crotamiton as a loxoprofen-containing patch.
The above patent is aimed at providing a loxoprofen-containing patch which has high pharmaceutical stability and reduced skin irritation by blending crotamiton with the aqueous base for the patch to increase solubility of loxoprofen in the preparation; however, sufficient transdermal absorption of loxoprofen as an active ingredient was not achieved.    [Patent Document 1] Japanese Patent Application Laid-Open No. Hei 10-120560
Accordingly, there is currently a demand for further improved external loxoprofen-containing patches which have high stability in the preparation and excellent transdermal absorption of loxoprofen.